Coolant Hose Rubber Composition for Low Coolant Conductivity
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Solution Overview
Problem
Conventional sulfur-vulcanized ethylene-propylene copolymer rubber compositions for vehicle coolant transport hoses lead to the extraction of unreacted vulcanization accelerator residues and decomposition products into the coolant, causing clogging of filters and increased coolant conductivity, which are detrimental to vehicle cooling systems and fuel cell systems.
Innovation Solution
A sulfur-vulcanized rubber composition for vehicle coolant transport hoses using a specific combination of high molecular weight vulcanization accelerators, such as dithiocarbamate, thiuram, and sulfenamide, in controlled proportions to minimize the extraction of residues into the coolant, thereby preventing filter clogging and conductivity issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sulfur vulcanization is used for cost advantage, then manufacturing cost is reduced, but unreacted vulcanization accelerator residues are extracted into coolant causing filter clogging and increased conductivity
Solution Approach 1:
The patent changes the molecular weight parameter of the vulcanization accelerator from conventional low molecular weight to high molecular weight (380 or more). This parameter change reduces the extractability of the accelerator residues into the coolant, thereby preventing filter clogging and conductivity increase while maintaining sulfur vulcanization cost advantages
Solution Approach 2:
The patent uses a composite vulcanization accelerator system combining multiple types (dithiocarbamate, thiuram, sulfenamide) with high molecular weights. This composite approach optimizes both the vulcanization performance and the reduction of extracted components, resolving the contradiction between cost-effectiveness and harmful extraction
2Productivity
If conventional vulcanization accelerators are used, then vulcanization efficiency is maintained, but coolant conductivity increases due to extracted decomposition products
Solution Approach 1:
The patent changes the molecular weight parameter of the vulcanization accelerator to 380 or more, which significantly reduces the extractability into coolant. This parameter change maintains vulcanization efficiency while preventing conductivity increase, as the high molecular weight accelerators remain trapped in the rubber matrix
3Object-generated harmful factors
If high molecular weight vulcanization accelerators are used, then extractability into coolant is reduced, but vulcanization performance may be affected
Solution Approach 1:
The patent employs a composite system of multiple high molecular weight vulcanization accelerators (dithiocarbamate, thiuram, sulfenamide) in specific proportions. This composite approach ensures adequate vulcanization performance while maintaining low extractability, as different accelerator types complement each other's functions
Solution Approach 2:
The patent optimizes the molecular weight parameter (380 or more) and the proportion (75% or more of total accelerator) to achieve the right balance between vulcanization performance and reduced extractability, ensuring both reliability and low harmful extraction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses the extraction of unreacted residues and decomposition products, ensuring the hose's performance and safety by maintaining low coolant conductivity and preventing adverse effects on vehicle cooling and fuel cell systems.
Implementation Method 1
sulfur vulcanization
Implementation Method 2
decomposition products of the vulcanization accelerator
Implementation Method 3
extracted (eluted) into the coolant
Data Source
AI summary
A sulfur-vulcanized rubber composition contains an ethylene-propylene copolymer rubber (A) as a main component and a vulcanization accelerator (B) and serves as a material of an innermost layer of a vehicle coolant transport hose. The vulcanization accelerator (B) includes at least one vulcanization accelerator selected from a group consisting of (B-1) to (B-3) below in a specific proportion. (B-1) A dithiocarbamate vulcanization accelerator having a molecular weight of 380 or greater. (B-2) A thiuram vulcanization accelerator having a molecular weight of 380 or greater. (B-3) A sulfenamide vulcanization accelerator.